Cooling Circuit With Parallel Radiators

ABSTRACT

A cooling circuit comprises an engine and a parallel arrangement. The parallel arrangement comprises a first radiator to cool liquid engine coolant and a second radiator to cool liquid engine coolant. The first and second radiators are flow-parallel to one another.

FIELD OF THE DISCLOSURE

The present disclosure relates to engine cooling.

BACKGROUND OF THE DISCLOSURE

Emissions standards are becoming more stringent. Such standards have placed an increased heat-rejection demand on parallel arrangements of off-highway equipment.

SUMMARY OF THE DISCLOSURE

According to the present disclosure, a cooling circuit comprises a pump, an engine, a thermostat, and a parallel arrangement. The pump, the engine, the thermostat, and the parallel arrangement are positioned in flow-series with one another. The parallel arrangement comprises a first radiator to cool liquid engine coolant and a second radiator to cool liquid engine coolant. The first and second radiators are flow-parallel to one another.

The two radiators are configured to satisfy the heat-rejection requirements of the engine collectively. In addition, since two radiators are used instead of one, each radiator can have a physical size smaller than would be required of a single radiator to meet the heat-rejection requirements. Such reduced radiator size may assist with operator visibility and packaging on the vehicle, as compared to a larger, single radiator.

It is contemplated that the parallel arrangement may have more than two flow-parallel radiators.

The above and other features will become apparent from the following description and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the drawing refers to the accompanying figures in which:

FIG. 1 is a schematic view showing a cooling circuit of a vehicle in which a cooling circuit has a parallel arrangement with parallel radiators;

FIG. 2 is a schematic view of an embodiment of the parallel arrangement of FIG. 1;

FIG. 3A is a perspective view showing a work vehicle with the parallel arrangement of FIG. 2;

FIG. 3B is a top plan view showing a number of heat exchangers including the parallel radiators positioned along laterally opposite sides of the vehicle;

FIG. 4 is a perspective view showing the parallel arrangement of FIG. 2; and

FIGS. 5A and 5B are respectively top plan and elevation views of a hose structure.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, a work vehicle 10 (or other type of vehicle) shown, for example, diagrammatically in FIG. 1 has a cooling circuit 11. The circuit 11 has a pump 12, an engine 14, a thermostat 16, and a parallel arrangement 18. The pump 12, the engine 14, the thermostat 16, and the parallel arrangement 18 are positioned in flow-series with one another sequentially in that order in a flow loop. As such, the parallel arrangement is positioned fluidly between the thermostat 16 and the pump 12 and exclusive of the engine 14.

The parallel arrangement 18 comprises a first radiator 19 to cool liquid engine coolant and a second radiator 20 to cool liquid engine coolant. The first and second radiators 19, 20 are flow-parallel to one another to promote the performance of the parallel arrangement 18. The cooling circuit 11 has a fan 21 configured to advance air across the radiators 19, 20 to remove heat from the liquid engine coolant flowing through the radiators 19, 20.

The engine 14 is an internal combustion engine (e.g., diesel engine) that powers a number of powered systems of the vehicle 10 (e.g., propulsion, hydraulics). The engine 14 generates heat during operation.

The cooling circuit 11 is configured to cool the engine 14. The engine 14 has internal cooling passages through which engine coolant flows. The pump 12 is configured to pump the liquid engine coolant through the circuit 11, including the internal cooling passages of the engine 14.

Heat generated by the engine 14 is transferred to the engine coolant. When the temperature of the coolant is below the start-to-open temperature of the thermostat 16, located at or near a coolant outlet of the engine 14, the thermostat 16 directs the coolant to a bypass 23 which routes the coolant back to the pump 12 for cycling through the engine 14, bypassing the parallel arrangement 18, to warm up the engine 14. When the temperature of the coolant exceeds the start-to-open temperature of the thermostat 16, the thermostat 16 opens at least partially and directs coolant to the parallel arrangement 18 to cool the engine coolant.

A heating system for heating an operator's station of the vehicle 10 may be included in the cooling circuit 11. In such a case, a radiator in the form of a heater core 22 of the heating system remote from the arrangement 18 is fluidly coupled to the engine 14 and the pump 12 therebetween. When a control valve (not shown) of the heating system is opened at least partially (e.g., manually by an operator at the operator's station or automatically), engine coolant flows from the engine 14 through the heater core 22 to the pump 12. A fan 24 of the vehicle 10 is configured to advance air across the heater core 22 into the operator's station to heat the interior of the operator's station.

The parallel arrangement 18 is configured to cool liquid engine coolant. The parallel arrangement 18 has a first node 26, a second node 28, a first flow path 30 from the first node 26 to the second node 28, and a second flow path 32 from the first node 26 to the second node 28. The first radiator 19 is included in the first flow path 30. The second radiator 20 is included in the second flow path 32. The first and second flow paths 30, 32 are flow-parallel to one another between the first and second nodes 26, 28. In FIG. 1, the lines interconnecting the node 26 and the radiators 19, 20 and interconnecting the node 28 and the radiators 19, 20 are merely diagrammatic in that any differences in the lengths of those lines are of no significance.

The parallel arrangement 18 may be configured in a variety of ways. Referring to FIG. 2, an embodiment of the arrangement 18 is shown, for example, as a parallel arrangement 118 with parallel radiators 119, 120. The parallel arrangement 118 is configured to provide equal flow distribution between the two radiators 119, 120 to optimize the performance of each radiator 119, 120.

Referring to FIGS. 2 and 4, the parallel arrangement 118 has a first node 126, a second node 128, a first flow path 130 from the first node 126 to the second node 128, and a second flow path 132 from the first node 126 to the second node 128. The first radiator 119 is included in the first flow path 130. The second radiator 120 is included in the second flow path 132. The first and second flow paths 130, 132 are flow-parallel to one another between the first and second nodes 126, 128. In order to provide equal flow rates through the two radiators 119, 120, the first and second flow paths 130, 132 are equal in flow resistance.

To achieve equality in flow resistance, the first and second radiators 119, 120 are identical to one another, and the plumbing between the first node 126 and the first and second radiators 119, 120 and the plumbing between the second node 128 and the first and second radiators 119, 120 mirror one another. As such, the first and second flow paths 130, 132 are equal in length. Using identical radiators 119, 120 also promotes symmetry in the packaging of the radiators 119, 120 and cost efficiency (as compared to potential higher costs known sometimes to be associated with non-identical components).

The first and second nodes 126, 128 are positioned respectively adjacent to opposite radiators 119, 120, FIG. 2 being representative of such nodal positioning. Positioning the nodes 126, 128 in this manner may be useful to accommodate the layout of the cooling section of the vehicle or other constraints.

The arrangement 118 is configured for use in, for example, an articulated four-wheel drive loader, or other vehicle, having the cooling circuit 11. Exemplarily, such a loader has a front section and a rear section articulated to the front section. The vehicle is steered hydraulically (or otherwise) by relative movement between the front and rear sections about the articulation axis. The front section has a boom and a bucket or other work tool coupled to the boom. The rear section has the operator's station, an engine compartment rearward of the operator's station and containing the engine 14, and a cooling package 170 (FIG. 3A) rearward of the engine compartment. The engine compartment contains the engine 14 and the thermostat 16 and pump 12 which are mounted to the engine 14. A wall separates the engine compartment from the cooling package 170.

The cooling circuit 11 may have a surge tank (not shown). In such a case, the radiators 119, 120 and the engine 14 are coupled fluidly to the surge tank for removal of air therefrom via separate hoses coupled fluidly between the surge tank and the top of the radiator 119, the top of the radiator 120, and the engine 14 at a point upstream of the thermostat 16, respectively. The bottom of the surge tank is coupled fluidly to the pump 12 via a hose to provide positive pressure on the suction side of the pump 12 to prevent or otherwise reduce the risk of pump cavitation. A hose is coupled fluidly to the pressure-relief cap of the surge tank in the event that the pressure in the surge tank reaches a predetermined over-pressure.

Referring to FIGS. 3A and 3B, the radiators 119, 120 may be included in the cooling package 170 as two of the heat exchangers thereof. The cooling package 170 is configured, for example, as a generally box-shaped plenum structure and has a number of heat exchangers, a fan 121, and an interior plenum 172. The fan 121 provides a rear portion of the plenum 172. A front portion of the plenum 172 includes a combination cooler unit 174, having a transmission oil cooler and a hydraulic oil cooler which are adjacent to one another and fastened to another (e.g., bolted), and two axle coolers 178, the axle cooler 178 being for cooling respectively the front and rear axles of the vehicle and positioned respectively laterally outwardly and adjacent to the lateral sides of the combination cooler unit 174. A top portion of the plenum 172 includes a charge-air-cooler 180. A bottom portion of the plenum 172 includes a floor panel 182. A left portion of the plenum 172 includes the first or left radiator 119 and an air conditioner condenser 184 pivotally mounted and positioned laterally outwardly relative to the first radiator 119. A right portion of the plenum 172 includes the second or right radiator 120. As such, the first radiator 119 and the second radiator 120 are positioned respectively along laterally opposite sides 185 of the loader. The fan 121 is operable to advance air past the heat exchangers of the cooling package 170 through the plenum 172 and out the rear of the vehicle.

Referring to FIGS. 3B and 4, a radiator-supply hose 186 is clamped or otherwise coupled to an outlet of the engine 14 in which the thermostat 16 is positioned and an upper left bulkhead 188 to route coolant from the engine 14 to the upper left bulkhead 188. A radiator-return hose 190 is clamped or otherwise coupled to a lower right bulkhead 192 and the pump 12 mounted to the engine 14 to route coolant from the lower right bulkhead 192 to the pump 12. Hoses 186, 190 are routed through a wall between the engine and cooling sections.

The bulkheads 188, 192 are positioned respectively toward opposite sides of the front portion of the plenum 172. The upper left bulkhead 188 is positioned above the left axle cooler 178, and the lower right bulkhead 192 is positioned below the right axle cooler 178. Such positioning of the bulkheads 188, 192 accommodates the layout of the front wall of the plenum 172 and the respective high and low positioning of the radiator inlets 138, 146 and outlets 142, 150.

Each bulkhead 188, 192 has a bulkhead plate (steel) fastened (e.g., bolted) to an upper side plate of a respective frame portion of the cooling package 170 and a tube (steel) welded to and extending through the bulkhead plate and the upper side plate, providing a first tubular portion on one side of the plate external to the plenum 72 and a second tubular portion on the opposite side of the plate internal to the plenum 172. The radiator-supply hose 186 is clamped or otherwise coupled to the first tubular portion of the upper left bulkhead 188, and the radiator-return hose 190 is clamped or otherwise coupled to the first tubular portion of the lower right bulkhead 192.

Referring to FIG. 4, plumbing inside the plenum 172 is configured such that the first and second nodes 126, 128 are positioned respectively adjacent to opposite radiators 119, 120. The first flow path 130 has a first plumbing inlet section 136 having a first length from the first node 126 to a first inlet 138 of the first radiator 119 and a first plumbing outlet section 140 having a second length unequal to the first length from a first outlet 142 of the first radiator 119 to the second node 128. The second flow path 132 has a second plumbing inlet section 144 having the second length from the first node 126 to a second inlet of the second radiator 120 and a second plumbing outlet section 148 having the first length from a second outlet 150 of the second radiator 120 to the second node 128.

As such, the first node 126 is fluidly coupled to the first inlet 138 and the second inlet 146 and is closer to the first inlet 138 than the second inlet 146 such that the first and second inlets 138, 146 are non-equidistant from the first node 126, and the second node 128 is fluidly coupled to the first outlet 142 and the second outlet 150 and is closer to the second outlet 150 than the first outlet 142 such that the first and second outlets 142, 150 are non-equidistant from the second node 128.

The plumbing inside the plenum has an upper hose structure 152 and a lower hose structure 154, each made, for example, of rubber. Exemplarily, the upper and lower hose structures 152, 154 are identical to one another in structure, but mirror one another in orientation. The upper and lower hose structures 152, 154 are, for example, generally Y-shaped. The upper hose structure 152 has the first node 126, the first plumbing inlet section 136, the second plumbing inlet section 144, and a first connector section 156 interconnecting the first node 126 and the second (plenum-internal) tubular portion of the upper left bulkhead 188. The lower hose structure 154 has the second node 128, the first plumbing outlet section 140, and the second plumbing outlet section 148, and a second connector section 158 interconnecting the second node 128 and the second (plenum-internal) tubular portion of the lower right bulkhead 192.

Referring to FIGS. 5A and 5B, each hose structure 152, 154 has a larger-outer diameter (OD) hose 162 and three smaller-OD hoses 164-1, 164-2, 164-3 coupled (e.g., vulcanized) to the larger-OD portion 162, as shown, for example, with respect to upper hose structure 152. With respect to the upper hose structure 152, the smaller-OD hoses 164-1, 164-2, 164-3 are clamped or otherwise coupled respectively to the second (plenum-internal) tubular portion of the upper left bulkhead 188, the inlet 138 of the first radiator 119, and the inlet 146 of the second radiator 120 and cooperate with the larger-OD hose 162 to provide respectively the connector section 156, the first plumbing inlet section 140, and the second plumbing inlet section 144. With respect to the lower hose structure 154, the smaller-OD hoses 164-1, 164-2, 164-3 are clamped or otherwise coupled respectively to the second (plenum-internal) tubular portion of the lower right bulkhead 192, the outlet 142 of the first radiator 119, and the outlet 150 of the second radiator 120 and cooperate with the larger-OD hose 162 to provide respectively the connector section 158, the first plumbing outlet section 140, and the second plumbing outlet section 148.

A hose support 194 supports the upper hose structure 152 to prevent excessive sagging of the upper hose structure 152 when, for example, the hose structure 152 contains engine coolant. The hose support 194 has a split ring and an L-shaped bracket. The split ring has two ends which separate to receive an intermediate portion of the smaller-OD hose 164-3 into the ring. The split ring is mounted to the L-shaped bracket. The ends of the ring are configured as two tabs contacting one another in face-to-face relation (the two tabs are approximated in FIG. 4 as a single tab for ease of illustration, it being understood that the ring has two tabs), and the two tabs are fastened to the L-shaped bracket using a threaded fastener extending through the two tabs and the bracket. The bracket is fastened to an upper plate (steel) using a threaded fastener extending through the bracket into a threaded sleeve welded to the upper plate. The upper plate extends along the top of the combination cooler unit 174 and is welded to the upper side plate.

Illustratively, a drain hose 196 is provided to drain the radiators 119, 120. A petcock is attached to the bottom of the radiator 120, and the drain hose 196 is attached to the petcock. Upon opening of the petcock, the radiator 120 can be drained as well as the radiator 119 via the lower hose structure 154. The hose 196 may be tie-banded or otherwise coupled (tie-band not shown) to a suitable structure of the vehicle 10 such as, for example, a anchor that may be welded to the floor panel 182 or other portion of the cooling package 170 (the anchor may be, for example, a slender U-shaped rod having the curved base and termini of the U shape welded to the panel 182 and having its legs bent to receive the tie-band between the panel 182 and the legs). In other embodiments, there may be a drain hose for each radiator 119, 120 with an associated petcock attached to the bottom of that radiator 119, 120.

Alternatively, in some cooling package configurations, the first node 126 may be positioned mid-way between the first and second inlets 138, 146 such that the first and second inlets 138, 146 are equidistant from the first node 126, and the second node 128 may be positioned mid-way between the first and second outlets 142, 150 such that the first and second outlets 142, 150 are equidistant from the second node 128. Positioning the nodes 126, 128 at the mid-points with symmetric upper plumbing, symmetric lower plumbing, and identical radiators 119, 120 in the flow paths 130, 132 would provide equal flow resistance, and thus equal flow distribution, promoting the performance of the radiators 119, 120.

Using mirrored or symmetric plumbing and identical radiators 119, 120 provides equal flow resistance in the flow paths 130, 132 without use of orifices to control flow distribution. Orifices would add complexity and cost and would introduce potential variation between parts due to manufacturing tolerances with potential corresponding effects on flow resistance and distribution. Nonetheless, employment of orifices may be operationally acceptable in the absence of mirrored or symmetric plumbing or if non-identical radiators are used.

In other embodiments of the arrangement 18, the arrangement may have unequal flow distribution between the two radiators due to unequal flow resistance in the two flow paths of the arrangement, yet may be considered in some applications to provide adequate cooling performance. The two radiators may be identical, but the nodes of the arrangement may be positioned between the radiators such that the flow paths are of unequal length and thus unequal flow resistance (e.g., both nodes positioned closer to one radiator than the other).

In the parallel arrangement 18 and the embodiments thereof (including arrangement 118), the two flow-parallel radiators are configured to satisfy the heat-rejection requirements of the engine 14 collectively. In addition, since two radiators are used instead of one, each radiator can have a physical size smaller than would be required of a single radiator to meet the heat-rejection requirements. Such reduced radiator size may assist with operator visibility and packaging on board the vehicle 10. A single radiator may have a rather large size, negatively affecting operator visibility (e.g., when the radiator is rearward of the operator's station or forward of the operator's station, such as under the hood, either centered on the vehicle fore-aft centerline so as to be generally perpendicular thereto or positioned more to one side of the centerline than the other). Two radiators may have a smaller size presenting less of a visibility obstruction than a single radiator. Further, the two smaller radiators may be positioned symmetrically along laterally opposite sides of the vehicle, such as, for example, in the box-shaped cooling package 170 in which a single larger radiator may not fit within the size constraints of the package 170.

It is contemplated that the parallel arrangements disclosed herein may have more than two flow-parallel radiators.

While the disclosure has been illustrated and described in detail in the drawings and foregoing description (welds not shown in drawings but understood), such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. It will be noted that alternative embodiments of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the present invention as defined by the appended claims. 

1. A cooling circuit, comprising: a pump, an engine, a thermostat, and a parallel arrangement, wherein the pump, the engine, the thermostat, and the parallel arrangement are positioned in flow-series with one another, the parallel arrangement comprises a first radiator to cool liquid engine coolant and a second radiator to cool liquid engine coolant, and the first and second radiators are flow-parallel to one another.
 2. The cooling circuit of claim 1, wherein the parallel arrangement comprises a first node, a second node, a first flow path from the first node to the second node, a second flow path from the first node to the second node, the first radiator is included in the first flow path, the second radiator is included in the second flow path, and the first and second flow paths are flow-parallel to one another between the first and second nodes and equal in flow resistance.
 3. The cooling circuit of claim 2, wherein the first and second flow paths are equal in length.
 4. The cooling circuit of claim 3, wherein the first flow path comprises a first plumbing inlet section having a first length from the first node to a first inlet of the first radiator and a first plumbing outlet section having a second length unequal to the first length from a first outlet of the first radiator to the second node, and the second flow path comprises a second plumbing inlet section having the second length from the first node to a second inlet of the second radiator and a second plumbing outlet section having the first length from a second outlet of the second radiator to the second node.
 5. The cooling circuit of claim 1, wherein the first and second radiators are identical to one another.
 6. A work vehicle comprising the cooling circuit of claim
 1. 7. The work vehicle of claim 6, wherein the first radiator and the second radiator are positioned respectively along opposite sides of the work vehicle. 